U.S. patent application number 16/804910 was filed with the patent office on 2020-11-19 for guide device for a cooling fluid flowing around winding heads of an electrical machine, and electrical machine.
The applicant listed for this patent is VALEO SIEMENS EAUTOMOTIVE GERMANY GMBH. Invention is credited to Nils KRAIS, Philipp SONTGERATH.
Application Number | 20200366147 16/804910 |
Document ID | / |
Family ID | 1000004683964 |
Filed Date | 2020-11-19 |
United States Patent
Application |
20200366147 |
Kind Code |
A1 |
KRAIS; Nils ; et
al. |
November 19, 2020 |
GUIDE DEVICE FOR A COOLING FLUID FLOWING AROUND WINDING HEADS OF AN
ELECTRICAL MACHINE, AND ELECTRICAL MACHINE
Abstract
A guide device (1) for a cooling fluid flowing around winding
heads (28) of an electrical machine (21), including a body (2),
with a recess (4) delimited by an inner edge (3) for guiding
through a shaft of the electrical machine (21), and a guide element
(5), which protrudes from the body (2) in the axial direction and
extends in the peripheral direction in a radial position lying
between the inner edge (3) and an outer edge (6) of the body
(2).
Inventors: |
KRAIS; Nils; (Strahlungen,
DE) ; SONTGERATH; Philipp; (Niederkruchten,
DE) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
VALEO SIEMENS EAUTOMOTIVE GERMANY GMBH |
Erlangen |
|
DE |
|
|
Family ID: |
1000004683964 |
Appl. No.: |
16/804910 |
Filed: |
February 28, 2020 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02K 9/193 20130101;
H02K 3/24 20130101 |
International
Class: |
H02K 3/24 20060101
H02K003/24; H02K 9/193 20060101 H02K009/193 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2019 |
DE |
10 2019 113 091.3 |
Claims
1. A guide device (1) for a cooling fluid flowing around winding
heads (28) of an electrical machine (21), comprising a body (2),
with a recess (4) delimited by an inner edge (3) for guiding
through a shaft of the electrical machine (21), and a guide element
(5), which protrudes from the body (2) in the axial direction and
extends in the peripheral direction in a radial position lying
between the inner edge (3) and an outer edge (6) of the body
(2).
2. The guide device according to claim 1, further comprising a
second guide element (7), which protrudes from the body (2) in the
axial direction and extends in the peripheral direction in a second
radial position lying between the first radial position and the
outer edge (6) of the body (2).
3. The guide device according to claim 2, wherein the centres (17,
18) in the peripheral direction of the guide elements (5, 7) are
arranged so as to be connectable by a line (19) traversing the
centre point (20) of the recess (4).
4. The guide device according to claim 2, wherein an outlet opening
(11) for the cooling fluid is formed in the region of the centre
(18) in the peripheral direction of the second guide element
(7).
5. The guide device according to claim 4, wherein the second guide
element (7) has a radial indentation (12), which opens into the
outlet opening (11) formed in the body (2).
6. The guide device according to claim 2, wherein the first guide
element (5) and the second guide element (7) form one or two
overlap region(s) (16a, 16b) extending in the peripheral
direction.
7. The guide device according to claim 1, wherein a radially
outwardly pointing elevation (13) is formed at the free end of the
first guide element (5) and/or a radially inwardly pointing
elevation (14) is formed at the free end of the second guide
element (7).
8. The guide device according to claim 1, which is formed from a
plastics material.
9. An electrical machine (21), comprising a stator (22) having
stator windings (27) and a guide device (1) according to claim 1
arranged on an end face, wherein the first guide element (5) is
arranged inside of the winding heads (28) of the stator windings
(27) in the radial direction.
10. The electrical machine according to claim 9, wherein the guide
device further comprises a second guide element (7), which
protrudes from the body (2) in the axial direction and extends in
the peripheral direction in a second radial position lying between
the first radial position and the outer edge (6) of the body (2),
and the second guide element (7) is arranged outside of the winding
heads (28) in the radial direction.
11. The electrical machine according to claim 9, also comprising a
rotor (23) arranged inside the stator (22) so as to form an air gap
(24), wherein a radially outermost portion is positioned at the
free end of the first guide element (5) radially further outwardly
than the air gap (24).
12. The electrical machine according to claim 9, also comprising a
coolant feed (29), which is arranged in such a way that the cooling
fluid is conducted to the first guide element (5) in order to flow
around the first guide element in the peripheral direction.
13. The electrical machine according to claim 9, wherein the guide
device (1) is secured to an end plate (26) of the electrical
machine (21).
14. The electrical machine according to claim 9, wherein the stator
windings (27) are formed as hairpin windings.
Description
[0001] The invention relates to a guide device for a cooling fluid
flowing around winding heads of an electrical machine. The
invention also relates to an electrical machine.
[0002] When electrical machines are operated, stator windings heat
up due to their ohmic resistance. The higher a current that is
introduced into an electrical machine, the greater are the losses
that are caused by the heating. It is known in general to cool the
stator windings by means of a cooling fluid. It has already been
proposed in this regard to apply the cooling fluid in the form of a
jet to winding heads for the purpose of cooling.
[0003] Document DE 10 2017 211 135 A1 discloses an electrical
machine having a housing in which a stator having a plurality of
winding heads is arranged. The housing has a cooling channel
through which a cooling medium may flow. The cooling channel has a
circular or circle-segment-shaped annular channel portion, via
which the cooling medium is feedable through a plurality of
openings to part of the winding heads by spraying. A winding head
arranged at the bottom is covered by the cooling medium, which
collects in an oil sump.
[0004] As the winding heads are sprayed, however, the cooling fluid
passes, in the case of an electric machine of this kind, to the
shaft of the machine and is distributed within the electrical
machine as a result of the rotation of the electrical machine. In
so doing, the cooling fluid may pass into an air gap between a
rotor and a stator of the electrical machine and may cause
undesirable drag torques.
[0005] The object of the invention consequently is to provide a
possibility for the improved distribution of a cooling fluid in an
electrical machine.
[0006] This object is achieved in accordance with the invention by
a guide device for a cooling fluid flowing around winding heads of
an electrical machine, said guide device comprising a body with a
recess, which is delimited by an inner edge, for guiding through a
shaft of electrical machine, and a guide element, which protrudes
away from the body in an axial direction and extends in the
peripheral direction in a radial position lying between the inner
edge and an outer edge of the body.
[0007] The invention is based on the notion of guiding the cooling
fluid in the peripheral direction around the shaft and in
particular also around an air gap between a stator and a rotor of
the electrical machine by means of the guide element so that an
undesirable distribution of the cooling fluid by the rotating shaft
and infiltration into the air gap is hampered or entirely
suppressed. The distribution of the cooling fluid in the electrical
machine is thus improved; undesirable drag torques during operation
of the electrical machine may be reduced or avoided entirely.
[0008] The cooling fluid is typically a cooling liquid, in
particular a cooling oil.
[0009] In the case of the guide device according to the invention,
it is preferred if this also comprises a second guide element which
protrudes away from the body in the axial direction and extends in
the peripheral direction in a second radial direction lying between
the first radial position and the outer edge of the body. The
second guide element is used to receive the cooling fluid flowing
in the direction of a machine bottom as a result of the force of
gravity, once said cooling flow has passed down from the first
guide element, and allows the cooling fluid to flow selectively
around lower winding heads of the stator winding for cooling.
[0010] In this regard it is preferred if the centres of the guide
elements, in the peripheral direction, are arranged so as to be
connectable by a line traversing the centre point of the
recess.
[0011] It is also advantageous if, in the region of the centre, an
outlet opening for the cooling fluid is formed in the peripheral
direction of the second guide element. The cooling fluid may thus
be discharged effectively once it has reached the lowest point of
the second guide element. It is preferably provided here that the
second guide element has a radial indentation which opens into the
outlet opening formed in the body.
[0012] In accordance with an advantageous embodiment of the guide
device according to the invention it is provided that a radially
outwardly pointing elevation is formed at the free end of the first
guide element and/or a radially inwardly pointing elevation is
formed at the free end of the second guide element. The elevation
provides the corresponding guide element with a trough-like
structure, which, in the case of the second guide element, hampers
or prevents an axial escape of the cooling fluid from the guide
device, and in the case of the first guide element hampers or
prevents such an escape of the cooling fluid to an even greater
extent, and in particular enables a selective guidance of the
cooling fluid to the outlet opening.
[0013] Generally, it is preferred if the first guide element and
the second guide element form one or two overlap regions(s)
extending in the peripheral direction.
[0014] The first guide element preferably extends over at least 150
degrees, preferably at least 170 degrees, particularly preferably
at least 175 degrees, and/or at most 200 degrees, preferably at
most 185 degrees, particularly preferably at most 180 degrees, in
the peripheral direction. The second guide element may also extend
over at least 150 degrees, preferably at least 170 degrees,
particularly preferably at least 175 degrees, and/or at most 210
degrees, preferably at most 200 degrees, particularly preferably at
most 185 degrees, in the peripheral direction.
[0015] Alternatively, it may be provided that the first guide
element and/or the second guide element extends fully around the
recess in the peripheral direction.
[0016] The guide device according to the invention is particularly
preferably formed from a plastics material.
[0017] The object forming the basis of the invention is also
achieved by an electrical machine comprising a stator with stator
windings and a guide device according to the invention arranged on
an end face, wherein the first guide element is arranged inside of
the winding heads of the stator windings in the radial direction. A
further guide device according to the invention is expediently
arranged on the other end face.
[0018] It may be provided that the second guide element is arranged
outside of the winding heads in the radial direction.
[0019] In order to effectively hamper or prevent an infiltration of
the cooling fluid into the air gap, it is expedient if the
electrical machine according to the invention also comprises a
rotor arranged inside the stator so as to form an air gap, wherein
a radially outermost portion is positioned on the free end of the
first guide element radially further outwardly as compared to the
air gap.
[0020] A coolant feed is also preferably provided in the electrical
machine according to the invention and is arranged in such a way
that the cooling fluid is conducted to the first guide element in
order to flow around the first guide element in a peripheral
direction. It is particularly preferred if the coolant feed is
arranged in such a way that the cooling fluid is conducted in a
radial direction to the first guide element. The coolant feed may
have a plurality of feed openings, in particular distributed in the
peripheral direction.
[0021] The guide device is preferably secured to an end plate of
the electrical machine. The guide device may thus be easily
retrofitted in existing machine architectures.
[0022] Alternatively, however, it is also conceivable for the guide
device to be formed integrally with an end plate of the electrical
machine. In order to provide an electrical insulation of the guide
device, the end plate may be powder-coated, for example.
[0023] The stator windings are particularly preferably formed as
hairpin windings.
[0024] All embodiments of the guide device according to the
invention may be transferred to the electrical machine according to
the invention, and therefore the aforementioned advantages may be
attained also with the electrical machine.
[0025] Further advantages and details of the present invention will
become clear from the exemplary embodiments described hereinafter
and also with reference to the drawings. These are schematic
representations and show:
[0026] FIG. 1 a perspective view of an exemplary embodiment of the
guide device according to the invention;
[0027] FIG. 2 an axial plan view of the guide device shown in FIG.
1;
[0028] FIG. 3 a perspective sectional illustration of an exemplary
embodiment of the electrical machine according to the
invention;
[0029] FIG. 4 a perspective detailed view of the electrical machine
in the region of a first guide element of the guide device; and
[0030] FIG. 5 a perspective detailed view of the electrical machine
in the region of a second guide element of the guide device.
[0031] FIG. 1 is a perspective view of an exemplary embodiment of a
guide device 1.
[0032] The guide device comprises a body 2, with a recess 4
delimited by an inner edge 3, and also a first guide element 5,
which protrudes from the body in the axial direction and extends in
the peripheral direction in a first radial position lying between
the inner edge 3 and an outer edge 6 of the body 2. The guide
device 1 additionally also comprises a second guide element 7,
which protrudes from the body 2 in the axial direction and extends
in the peripheral direction in a second radial position lying
between the first radial position and the outer edge 6. The entire
body 2 is formed from an electrically insulating material, in this
particular case from a plastics material.
[0033] The body 2 to this end has an inner portion 8a, which is
delimited by the edge 3 and which extends along a radial plane, and
a second portion 8b, which is delimited by the outer edge 6 and is
axially angled relative to the first portion 8a. On a first side of
the body 2 visible in FIG. 1, the first guide element 5 is arranged
in a transition region between the first portion 8a and the second
portion 8b and is secured to the first portion 8a by means of
additional radially inwardly pointing reinforcement elements 9. The
second guide element 7 protrudes axially from the second portion 8b
of the body and is reinforced by additional radially outwardly
pointing reinforcement elements 10.
[0034] An outlet opening 11 is formed in the body 2 in the region
of the middle of the second guide element. The outlet opening 11
passes through the second portion 8b of the body 2. In addition, a
radially outwardly pointing indentation 12 is formed in the second
guide element 7 and opens into the outlet opening 11.
[0035] At a free end of the first guide element 5 there is formed a
radially outwardly pointing elevation 13, which will be explained
later in greater detail with reference to FIG. 4. At a free end of
the second guide element 7 there is formed a radially inwardly
pointing elevation 14, which will be explained later in greater
detail with reference to FIG. 5.
[0036] In addition, the body 2 has a plurality of through-openings
15 formed in the peripheral direction in its second portion 8b,
which are usable in order to secure the guide device 1 in position
or to introduce a cooling fluid to the first guide element.
[0037] FIG. 2 is an axial plan view of the side of the guide device
1 shown in FIG. 1.
[0038] The first guide element 5 extends in the peripheral
direction over an angular range of 180.degree.. By contrast, the
second guide element 7 extends over an angular range of
approximately 195.degree., such that the guide elements 5, 7 form
two overlap regions 16a, 16b. The centres 17, 18 of the guide
elements 5, 7 are arranged such that a line 19 connecting them
traverses the centre point 20 of the recess 4.
[0039] FIG. 3 is a perspective sectional illustration of an
exemplary embodiment of an electrical machine 21 in the region of a
first end face.
[0040] The electrical machine 21 comprises a stator 22 and a rotor
23, between which there is formed an air gap 24, and also a machine
housing 25, and an end plate 26. In FIG. 3 an A end plate is shown.
The electrical machine 21 has, on its second end face, a further
end plate (B end plate). A guide device 1 according to the
previously described exemplary embodiment is arranged on each of
these end plates 26. The electrical machine 21 is a prime mover for
an electrically drivable vehicle.
[0041] The stator 22 has stator windings 27, which are formed as
hairpin windings. Winding heads 28 of the stator windings 27
protrude from the stator 22 in the direction of the end plate 26.
The first guide element 5 is arranged radially inside of the
winding heads 28, and the second guide element 7 is arranged
radially outside of the winding heads 28.
[0042] The electrical machine 21 also has a coolant feed 29, which
is arranged in such a way that a cooling fluid is conducted to the
first guide element 5 in order to flow around the first guide
element in the peripheral direction. In the overlap regions 16a,
16b (see FIG. 2), the cooling fluid flows down from the first guide
element 5 to the second guide element 7 as a result of the force of
gravity acting in the direction of a machine bottom 30. From there,
the cooling fluid flows around the other winding heads 28 and
passes at the lowest point of the second element 7 into the outlet
opening 11 (see FIG. 1).
[0043] FIG. 4 is a perspective detailed view of the electrical
machine 21 in the region of the first guide element 5. As can be
seen, a radially outermost portion of the first guide element 5
lies radially further outwardly than the air gap 24. The elevation
13 prevents cooling fluid from escaping axially from the guide
device 1 and entering the air gap 24.
[0044] FIG. 5 is a perspective detailed view of the electrical
machine 21 in the region of the second guide element 7. Here, the
elevation 14 prevents cooling fluid from escaping axially from the
guide device 1 and from leaving the guide device 1 other than
through the outlet opening 11 (see FIG. 1).
* * * * *